Studies are continuing on the relation between ionic environment and metabolism of both normal glial cells and those derived from glial tumors using fluorometric techniques. The membrane properties of these glial cells are also under investigation with electrophysiological techniques. In addition, the fine structure, particularly the structural relations between the cells, are studied with electron microscopy. Microchemical analysis of glucose and amino acid metabolism in glial cells and their alteration by changes in the ionic environment are being investigated. Other studies are concerned with the anatomical and physiological basis of the neuronal control of an invertebrate smooth muscle.